Drug has potential to prevent alcoholics from relapsing

Washington, July 31 : An experimental drug blocks euphoric feelings prompted by drinking and could potentially prevent alcoholics from relapsing, after being tested on mice.

The next step will be to test the drug, CP 154,526, to see if it is safe for humans. If it clears that hurdle, researchers will start human trials to determine if the drug can prevent alcoholic relapse.

"We showed we could block behaviour in mice that resembles this increased euphoria even after the animals had been given a lot of alcohol," said Tamara Phillips, professor and vice chair of the behavioural neuroscience department at Oregon Health & Science University (OHSU).

Earlier research has shown that some people's brains become sensitised as a result of chronic exposure to alcohol. This change in the brain does not subside after people quit drinking. So when they begin consuming alcohol again, "they get a bigger jolt," Phillips said.

Alcohol consumption causes the body to release a substance known as "corticotrophin-releasing factor" or CRF. It activates receptors in the brain.

Phillips and her team determined that a brain receptor called CRF1 appears to be involved in this heightened pleasure sensation. They compared the responses of normal mice and mice bred without the CRF1 receptor to chronic doses of alcohol. Mice without the CRF1 receptor did not experience the euphoric jolt the normal mice demonstrated.

The research team also took normal mice with the CRF1 receptor and exposed them to chronic doses of alcohol. Before testing for the euphoric response, the researchers gave the mice an experimental drug called CP 154,526 - developed by Pfizer - which prevents CRF from reaching the brain receptor. This group of mice also did not experience the heightened reaction.

The results may be particularly applicable to stress-induced relapse. That's because the CRF1 receptor also triggers the body's response to stress.

This could have implications for PTSD (post-traumatic stress disorder) patients. "I think if you block this receptor, you might be able to decrease drinking in response to PTSD," Phillips said.

Phillips' study recently was published in the Proceedings of the National Academy of the Sciences.